Streptospondylus

Streptospondylus (meaning "reversed vertebra") is a genus of tetanuran theropod dinosaur known from the Late Jurassic period of France, 161 million years ago. It was a medium-sized predator.

Streptospondylus
Temporal range: Late Jurassic, 161 Ma
Streptospondylus altdorfensis
Tibia, astragalus and calcaneum of Streptospondylus altdorfensis
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Clade: Megalosauria
Genus: Streptospondylus
von Meyer, 1832
Species:
S. altdorfensis
Binomial name
Streptospondylus altdorfensis
von Meyer, 1832
Synonyms[1]

Discovery and naming

StreptospondylusNV
Restoration in its habitat

Streptospondylus was one of the first dinosaurs collected and was the first described, though not the first dinosaur named. It was not recognised as a theropod dinosaur until 2001.

In 1778, abbey Charles Bacheley (1716-1795), a Norman naturalist, reported the presence of fossil bones in the Callovo-Oxfordian formations exposed at the foot of the Vaches Noires cliffs between Villers-sur-Mer and Houlgate.[2][3] These fossil materials contained theropod vertebrae and marine crocodilian remains. After the death of Bacheley, his fossil cabinet was acquired by the "Ecole centrale de Rouen".[2] Louis-Benoît Guersent (1777–1848), professor of natural history in this school, drew the attention of Georges Cuvier to this remarkable fossil bones. With the agreement of the prefect of Seine-Inférieure, count Jacques Claude Beugnot, Guersent sent the collection to the Muséum National d'Histoire Naturelle in Paris. In 1800, these fossils were briefly mentioned by Georges Cuvier who misspelled the name of their former owner as Bachelet.[4]

In 1808, Cuvier scientifically described the theropod vertebrae as the first dinosaur remains ever. However, he considered them to be crocodilian and associated them with fossils of the Teleosauridae and the Metriorhynchidae.[5] In 1822, Cuvier by the work of Henry De La Bèche became aware that these finds were very disparate, stemming from different periods. He abstained from naming them but in 1824 concluded that there were two main types. In 1825 Étienne Geoffroy Saint-Hilaire accordingly named two crocodilian skulls as the genus Steneosaurus, the one, specimen MNHN 8900, becoming Steneosaurus rostromajor, the other, MNHN 8902, S. rostrominor.[6]

In 1832 however, the German paleontologist Christian Erich Hermann von Meyer split the material. Steneosaurus rostrominor was renamed Metriorhynchus geoffroyii while Steneosaurus rostromajor became Streptospondylus altdorfensis. To the last species the theropod remains were referred.[7] The generic name is derived from Greek στρεπτος/streptos, "reversed", and σπονδυλος/spondylos, "vertebra", alluding to the fact that the vertebrae differed from typical crocodile elements in being opisthocoel: convex in front and concave behind. The specific name refers to Altdorf where some teleosaurid remains had also been found. Von Meyer's name was the first binomial name (also) referring to a theropod.

Streptospondylus
Type specimen of S. cuvieri

In 1842 Richard Owen pointed out that von Meyer had been incorrect in changing the original specific name and created the correct combination Streptospondylus rostromajor for Streptospondylus altdorfensis. At the same time he created a second species: Streptospondylus cuvieri based on a single damaged vertebra from the Bajocian, found near Chipping Norton.[8] In 1861, Owen would refer the entire Cuvier material to S. cuvieri, despite the fact that if it were cospecific the name S. rostromajor would have priority. From that time S. cuvieri was generally accepted in the literature as the valid name, though some workers split off the theropod remains from the crocodilian bones, Edward Drinker Cope in 1867 naming a Laelaps gallicus and Friedrich von Huene in 1909 a Megalosaurus cuvieri.

In 1964, Alick Donald Walker discovered Owen's mistake, referring the entire theropod material to the new species Eustreptospondylus divesensis which, however, had a skull not belonging to the Cuvier material as the type specimen, MNHN 1920-7.[9] In 1977 Philippe Taquet created the genus Piveteausaurus for this species.

In 2001, Ronan Allain concluded that no connection could be proven between Piveteausaurus and the referred other theropod material from Normandy. He also pointed out that the skull von Meyer had based Streptospondylus altdorfensis on was in fact a composite of bones from two species, since named Steneosaurus edwardsi Deslongchamps 1866 and Metriorynchus superciliosum Blainville 1853 (Steel 1973). A lectotype had never been chosen from one of the composite parts to give the name Streptospondylus priority over either one of these species. Allain used this situation to remove all the crocodilian material from the Streptospondylus type by designating the complete (postcranial) theropod material as the lectotype. As Steneosaurus rostromajor had been based on the composite skull, the epithet rostromajor now no longer had priority over altdorfensis. This way in 2001 Streptospondylus altdorfensis became the valid name and type species of a theropod. Laelaps gallicus and Megalosaurus cuvieri are its objective junior synonyms.[1]

The lectotype specimens, MNHN 8605-09, 8787-89, 8793-94, 8907, were probably found at the coast in layers of the Falaises des Vaches Noires near Calvados, dating from the late Callovian or early Oxfordian, about 161 million years old. They consist of several vertebrae series, single vertebrae, a partial left pubis and limb elements. The longest vertebra has a length of 97 millimetres, indicating a total body length of about seven metres. Also a partial left femur, MNHN 9645, has been referred. Streptospondylus has been diagnosed by several osteological details, among which the possession of two hypapophyses on the, ventrally flat, anterior dorsal vertebrae and the particular connection between the astragalus and the tibia, without a posterior astragalar process but with a distinctive buttress on the tibia above the anterior process.

Streptospondylus major
Material referred to S. major by Owen

Owen also named two other species, S. major[8] (S. recentior is a museum label for syntype specimens [10]) and S. meyeri,[11] of which the former is based on iguanodont material. His S. cuvieri, of which the type specimen is lost, is today considered a nomen dubium.

In 2010 Gregory S. Paul renamed (as an informal name) Magnosaurus into Streptospondylus nethercombensis.[12]

Phylogeny

Earlier assigned to crocodilian groups, Streptospondylus was in the 20th century typically classified in the Megalosauridae.

Recent analyses indicate that Streptospondylus is a tetanuran theropod. Allain in 2001 suggested that it was closely related to Eustreptospondylus in the Spinosauroidea. Roger Benson in 2008 and 2010 concluded that whether it is a megalosauroid, allosauroid, or a more primitive form cannot be determined because of its extremely fragmentary remains.[13] Later cladistic analysis by Benson and colleagues from 2010 indicated that Streptospondylus was the sister species of Magnosaurus within the Megalosauridae.[14] Carrano et al. (2012) place Streptospondylus at Megalosauria incertae sedis due to its fragmentary nature.[15]

References

  1. ^ a b Allain R (2001). "Redescription de Streptospondylus altdorfensis, le dinosaure théropode de Cuvier, du Jurassique de Normandie [Redescription of Streptospondylus altdorfensis, Cuvier's theropod dinosaur from the Jurassic of Normandy]". Geodiversitas. 23 (3): 349–367.
  2. ^ a b Brignon, A. (2016) Abbé Bacheley and the discovery of the first dinosaurs and marine crocodilians from the Jurassic of the Vaches Noires (Callovian/Oxfordian, Normandy, France). Comptes Rendus Palevol 15 : 595–605 (in French with an abridged English version).
  3. ^ Brignon, A. (2016) Le premier "chasseur de dinosaures" en France : l'abbé Charles Bacheley (1716-1795). Fossiles: Revue française de Paléontologie 27 : 36-42.
  4. ^ Cuvier G (1800). "Sur une nouvelle espèce de crocodile fossile". Bulletin des Sciences, Société Philomathique de Paris. 2: 159.
  5. ^ Cuvier G (1808). "Sur les ossements fossiles de crocodiles et particulièrement sur ceux des environs du Havre et d'Honfleur, avec des remarques sur les squelettes de sauriens de la Thuringe". Annales du Muséum d’Histoire naturelle de Paris. XII: 73–110.
  6. ^ Geoffroy Saint-Hilaire E (1825). "Recherches sur l'organisation des gavials". Mémoires du Muséum national d’Histoire naturelle. 12: 97–155.
  7. ^ Meyer, H. von, 1832, Paleologica zur Geschichte der Erde, Frankfurt am Main, 560 p
  8. ^ a b Owen R (1842). "Report on British fossil reptiles". Report of the British Association for the Advancement of Science. 11: 60–204.
  9. ^ Walker A.D. (1964). "Triassic reptiles from the Elgin area: Ornithosuchus and the origin of carnosarus". Philosophical Transactions of the Royal Society of London. 248: 53–134. Bibcode:1964RSPTB.248...53W. doi:10.1098/rstb.1964.0009.
  10. ^ Mantell, G. A., 1851, Petrifactions and their teachings; or a hand-book to the Gallery of Organic remains of The British Museum, London, 496pp.
  11. ^ Owen, R., 1854a. Descriptive catalogue of the fossil organic remains of reptilia and pisces contained in the Museum of The Royal College of Surgeons of England: 184pp.
  12. ^ Paul, G.S. 2010. The Princeton Field Guide to Dinosaurs. Princeton University Press, 320 pp
  13. ^ Benson, R.B.J. (2010). "A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods". Zoological Journal of the Linnean Society. 158: 882. doi:10.1111/j.1096-3642.2009.00569.x.
  14. ^ Benson, R.B.J., Carrano, M.T and Brusatte, S.L. (2010). "A new clade of archaic large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to the latest Mesozoic". Naturwissenschaften. 97 (1): 71–78. Bibcode:2010NW.....97...71B. doi:10.1007/s00114-009-0614-x. PMID 19826771.CS1 maint: Multiple names: authors list (link) Supporting Information
  15. ^ M. T. Carrano, R. B. J. Benson, and S. D. Sampson. 2012. The phylogeny of Tetanurae (Dinosauria: Theropoda). Journal of Systematic Palaeontology 10(2):211-300
1830 in paleontology

Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1830.

Afrovenator

Afrovenator (; "African hunter") is a genus of megalosaurid theropod dinosaur from the middle Jurassic Period of northern Africa.

Allosauroidea

Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Metriacanthosauridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae. Allosauroids, alongside the family Megalosauroidea, were among the apex predators that were active during the Middle Jurassic to Late Cretaceous periods. Of the fourteen allosauroid taxa, five are known for specimens with relatively complete skulls; the taxa are Allosaurus, Sinraptor, Yangchuanosaurus, Carchardontosaurus, and Acrocanthosaurus. The most famous and best understood allosauroid is the North American genus Allosaurus.

The oldest-known allosauroid, Shidaisaurus jinae, appeared in the early Middle Jurassic (probably Bajocian stage) of China. The last known definitive surviving members of the group died out around 93 million years ago in Asia (Shaochilong) and South America (Mapusaurus), though the megaraptorans may belong to the group as well. Additional, but highly fragmentary, remains probably belonging to carcharodontosaurids have been found from the Late Maastrichtian (70-66 Ma ago) in Brazil. An alternative interpretation is to attribute the remains to abelisaurids, which share the distinct pattern of curved wrinkled enamel found in the Brazilian remains with the carcharodontosaurids. This similarity between abelisaurids and carcharodontosaurids means that a definitive match between the Brazilian fossil and carcharodontosaurids cannot be made.Allosauroids had long, narrow skulls, large orbits, three-fingered hands, and usually had "horns" or ornamental crests on their heads. Although allosauroids vary in size, the group maintains a similar center of mass and hip position on their bodies. Allosauroids also exhibit reptilian-style immune systems, secreting fibrin at injured sites to prevent infections from spreading through the bloodstream. This characteristic has been observed by examining injuries and infections on allosauroid bones. It is possible that allosauroids were social animals, as many remains of allosauroids have been found in close proximity to each other. Allosauroids were likely active predators, and from studying endocasts, probably best responded to odors and loud low-frequency noises.

Chipping Norton Formation

The Chipping Norton Formation is a geological formation in Europe. It dates back to the Middle Jurassic.

Christian Erich Hermann von Meyer

Christian Erich Hermann von Meyer (3 September 1801 – 2 April 1869), known as Hermann von Meyer, was a German palaeontologist. He was awarded the 1858 Wollaston medal by the Geological Society of London.

Dubreuillosaurus

Dubreuillosaurus is a genus of carnivorous dinosaur from the middle Jurassic Period. It is a megalosaurid theropod. Its fossils were found in France. The only named species, Dubreuillosaurus valesdunensis, was originally described as a species of Poekilopleuron, Poekilopleuron? valesdunensis, which is still formally the type species of the genus. It was later renamed Dubreuillosaurus valesdunensis when, in 2005, Allain came to the conclusion that it was not part of the genus Poekilopleuron. Its type specimen, MNHN 1998-13, is only rivalled in the number of preserved elements in this group by that of Eustreptospondylus. Dubreuillosaurus is considered to be the sister species of Magnosaurus. It did not show signs of insular dwarfism even though it was uncovered on an island.

Eustreptospondylus

Eustreptospondylus ( yoo-STREPT-o-spon-DY-ləs; meaning "true Streptospondylus") is a genus of megalosaurid theropod dinosaur, from the Oxfordian stage of the Late Jurassic period (some time between 163 and 154 million years ago) in southern England, at a time when Europe was a series of scattered islands (due to tectonic movement at the time which raised the sea-bed and flooded the lowland).

Hastings Beds

The Hastings Beds is a geological unit that includes interbedded clays, silts, siltstones, sands and sandstones in the High Weald of southeast England. These strata make up the component geological formations of the Ashdown Formation, the Wadhurst Clay Formation and the Tunbridge Wells Sand Formation. The term 'Hastings Beds' has been superseded and the component formations are included in the Wealden Group.The sediments of the Weald, including the Hastings Beds, were deposited during the Early Cretaceous Period, which lasted for approximately 40 million years from 140 to 100 million years ago. The Hastings Beds are of Early Berriasian to Late Valanginian age. The Group takes its name from the fishing town of Hastings in East Sussex.

Dinosaur remains are among the fossils that have been recovered from the included formations.

Hypselosaurus

Hypselosaurus (meaning 'highest lizard', from Greek ὑψηλός meaning 'high' or 'lofty' and σαυρος meaning 'lizard') was a dubious titanosaurian sauropod that lived in southern France during the Late Cretaceous, approximately 70 million years ago in the early Maastrichtian. Hypselosaurus was first described in 1846, but was not formally named until 1869, when Phillip Matheron named it under the binomial Hypselosaurus priscus. The holotype specimen includes a partial hindlimb and a pair of caudal vertebrae, and two eggshell fragments were found alongside these bones. Because of the proximity of these eggshells to the fossil remains, many later authors, including Matheron and Paul Gervais, have assigned several eggs from the same region of France all to Hypselosaurus, although the variation and differences between these eggs suggest that they do not all belong to the same taxon. Hypselosaurus has been found in the same formation as the dromaeosaurids Variraptor and Pyroraptor, the ornithopod Rhabdodon, and the ankylosaurian Rhodanosaurus, as well as indeterminate bones from other groups.

Leshansaurus

Leshansaurus is a genus of theropod dinosaur from the Mid to Late Jurassic Dashanpu Formation of what is now China. It was described in 2009 by a team of Chinese paleontologists. The type species is Leshansaurus qianweiensis. Fossils of Leshansaurus were discovered in strata from the Shangshaximiao Formation, a formation rich in dinosaur fossils. Li et al. referred this taxon to Sinraptoridae – a group of carnosaurian theropods, but it may it belong to Megalosauridae instead.

List of commonly used taxonomic affixes

This is a list of common affixes used when scientifically naming species, particularly extinct species for whom only their scientific names are used, along with their derivations.

-acanth, acantho-, -cantho: Pronunciation: /eɪkænθ/, /eɪkænθoʊ/. Origin: Ancient Greek ἄκανθα (ákantha). Meaning: spine.Examples: Acanthodes ("spiny base"); Acanthostega ("spine roof"); coelacanth ("hollow spine"); Acrocanthosaurus ("high-spined lizard"); Acanthoderes ("spiny neck")arch-, archi-, archo-, -archus: Pronunciation: /ark/, /arkoʊ/, /arkɪ/, /arkəs/. Origin: Ancient Greek ἀρχός (arkhós), meaning: ruler; ἀρχικός (arkhikós), meaning: ruling. Used for exceptionally large or widespread animals.Examples: Archelon ("ruling turtle"); Architeuthis ("ruling squid"); Archosaur ("ruling lizard"); Andrewsarchus ("Andrews's ruler")archaeo-: Pronunciation: /arkiːɒ/, /arkiːoʊ/ . Origin: Ancient Greek ἀρχαῖος (arkhaîos). Meaning: ancient. Used for early versions of animals and plants.Examples: Archaeopteryx ("ancient wing"); Archaeoindris ("ancient Indri"); Archaeopteris ("ancient fern")arthro-: /arθroʊ/. Origin: Ancient Greek ἄρθρον (árthron). Meaning: Joint. Often used for animals with exoskeletons.Examples: Arthrospira ("jointed coil"); Arthropleura ("jointed rib"); arthropod ("jointed foot")aspido-, -aspis: Pronunciation: /əspɪdoʊ/, /əspɪs/. Origin: Ancient Greek ἀσπίς (aspís). Meaning: shield. The suffix "=aspis" is used to describe armored fish.Examples: Aspidochelone ("shield turtle"); Cephalaspis ("head shield"); Sacabambaspis ("Sacabamba shield"); Brindabellaspis ("Brindabella shield")-avis: Pronunciation: /əvɪs/. Origin: Latin avis. Meaning: Bird.Examples: Protoavis ("first bird"); Argentavis ("Argentine bird"); Eoalulavis ("little-winged dawn bird")brachi-, brachy-: pronunciation: /brækɪ/. Origin: Ancient Greek βραχύς, βραχίων (brakhús, brakhíōn). Meaning: short, and the short part of the arm, or upper arm, respectively. Used in its original meaning, and also to mean "arm".Examples: Brachylophosaurus ("short-crested lizard"); Brachiosaurus ("arm lizard"); Brachyceratops ("short-horned face")bronto-: Pronunciation: /brɒntoʊ/. Origin: Ancient Greek βροντή (brontḗ). Meaning: thunder. Used for large animals.Examples: Brontosaurus ("thunder lizard"), Brontotherium ("thunder beast"), Brontoscorpio ("thunder scorpion")-canth, cantho-: see -acanth, acantho--cephalus, cephalo-, -cephale, -cephalian: Pronunciation: /sɛfələs/, /sɛfəloʊ̯/, /sɛfəli:/ /sɛfeɪliːən/. Origin: Ancient Greek κεφαλή (kephalḗ). Meaning: head.Examples: Euoplocephalus ("well-protected head"), Pachycephalosaurus ("thick headed lizard"), Amtocephale ("Amtgai head"); Therocephalian ("beast-headed")-ceras, cerat-, -ceratus : Pronunciation: /sɛrəs/, /sɛrət/, /sɛrətəs/. Origin: Ancient Greek κέρας (kéras). Meaning: horn. Used for many horned animals, but most notably ceratopsians.Examples: Triceratops ("three-horned face"), Orthoceras ("straight horn") Megaloceras ("big horn") Ceratosaurus ("horned lizard") Microceratus ("small horned")cetio-, -cetus: Pronuncuation: /sɛtɪoʊ/, /siːtəs/. Origin: Ancient Greek κῆτος (kētos). Meaning: sea-monster. The suffix "-cetus" is used for whales or whale ancestors, while the prefix "cetio-" is used for whale-like or large animals.Examples: Cetiosaurus ("whale lizard"); Ambulocetus ("walking whale"); Pakicetus ("Pakistan whale")-cheirus: Pronunciation: /kaɪrəs/. Origin: χείρ (kheír). Meaning: hand.Examples: Deinocheirus ("terrible hand"); Ornithocheirus ("bird hand"); Austrocheirus ("southern hand"); Haplocheirus ("simple hand")chloro-: Pronunciation: /kloroʊ/. Origin: Ancient Greek χλωρός (khlōrós). Meaning: green.Examples: Chlorophyta ("green plant") Chlorophyll ("green leaf")coel-: Pronunciation: /siːl/ or /sɛl/ . Origin: Ancient Greek κοῖλος (koîlos). Meaning: hollow.Examples: coelacanth ("hollow spine"); Coelodonta ("hollow tooth"); Coelophysis ("hollow form") Amphicoelias (¨hollow at both ends¨)cyclo-: Pronunciation: /saɪkləʊ/ (or /saɪklɒ/). Origin: Ancient Greek κύκλος (kúklos). Meaning: circle.Examples: Cyclomedusa ("circle Medusa"); Cyclostomata ("circle mouth")cyn-, -cyon: Pronunciation: /saɪn/, /saɪɒn/. Origin: Ancient Greek κύων (kúon). Meaning: dog. Used for dogs or dog-like creatures.Examples: Cynodont ("dog tooth"); Cynopterus ("dog wing"); Arctocyon ("bear dog")-dactyl, -dactylus: Pronunciation: /dæktəl/, /dæktələs/. Origin: Ancient Greek δάκτυλος (dáktulos). Meaning: finger, toe.Examples: artiodactyl ("even toe"); Pterodactylus ("wing finger"); perissodactyl ("uneven toe")-deres: Origin: Ancient Greek δέρη (dére). Meaning: neck, collar.Examples: Acanthoderes ("spiny neck")-derm: Pronunciation: /dɜrm/. Origin: Ancient Greek δέρμα (dérma). Meaning: animal hide. Used for skin.Examples: placoderm ("plated skin"); echinoderm ("hedgehog skin"); ostracoderm ("shell skin")deino-: See dino-, deino-.

dendro-, -dendron, -dendrum: Pronunciation: /dɛn.dɹoʊ/, /ˈdɛndɹən/, /dɛndɹəm/. Origin: Ancient Greek δένδρον (déndron). Meaning: tree.Examples: Rhododendron ("rose tree"); Liriodendron ("lily tree"); Dendrocnide ("tree nettle"); Epidendrum ("above tree") Lepidodendron (¨scaled tree¨)di-: Pronunciation: /daɪ/. Origin: Ancient Greek δίς (dís). Meaning: twice. Used to indicate two of something.Examples: Dilophosaurus ("twice crested lizard"); Diceratops ("two-horned face") diapsid ("two arches")dino-, deino-: Pronunciation: /daɪnoʊ/. Origin: Ancient Greek δεινός (deinós). Meaning: "terrible", "formidable". Used for presumably fearfully large or dangerous animals or animal parts.Examples: dinosaur ("terrible lizard"), Dinofelis ("terrible cat"), Deinonychus ("terrible claw"), Deinocheirus ("terrible hand")diplo-: Pronunciation: /dɪploʊ/, /dɪplo/. Origin: Ancient Greek διπλόος, διπλοῦς (diplóos, diploûs). Meaning: double.Examples: Diplodocus ("double beam"); Diplopoda ("double feet"); Diplomonad ("double unit")-don, -dont, -donto-: See -odon, -odont, -odonto-.

dromaeo-, -dromeus: Pronunciation: /droʊmɪoʊ/, /droʊmɪəs/ Origin: Ancient Greek δρομαῖος (dromaîos). Meaning: runner.Examples: Dromaeosaurus ("runner lizard"); Kulindadromeus ("Kulinda runner"); Thalassodromeus ("sea runner")eo-: Pronunciation: /iːoʊ̯/. Origin: Ancient Greek ἠώς (ēṓs). Meaning: dawn. Used for very early appearances of animals in the fossil record.Examples: Eohippus ("dawn horse"); Eomaia ("dawn Maia"); Eoraptor ("dawn seizer")-erpeton: Pronunciation: /ɜrpətɒn/. Origin: Ancient Greek ἑρπετόν (herpetón). Meaning: reptile (literally, "creeping thing"); used for amphibians.Examples: Hynerpeton ("Hyner creeper"); Greererpeton ("Greer creeper"); Arizonerpeton ("Arizona creeper")eu-: Pronunciation: /iːu̟/. Origin: Ancient Greek εὖ (eû). Meaning: "good", "well"; also extended via New Latin to mean "true". Used in a variety of ways, often to indicate well-preserved specimens, well-developed bones, "truer" examples of fossil forms, or simply admiration on the part of the discoverer.Examples: Euparkeria ("Parker's good [animal]") Euhelopus ("good marsh foot") Eustreptospondylus ("true Streptospondylus")-felis: Pronunciation: /fiːlɪs/. Origin: Latin felis, feles. Meaning: cat. "Felis" alone is the genus name for the group that includes the domestic cat.Examples: Dinofelis ("terrible cat"); Pardofelis ("leopard cat");-form, -formes: Pronunciation: /foʊrm/, /foʊrms/. Origin: Latin forma. Meaning: shape, form. Used for large groups of animals that share similar characteristics.Examples: Galliformes ("chicken form"); Anseriformes ("goose form"); Squaliformes ("shark form")giga-, giganto-: Pronunciation: /d͡ʒaɪgə/, /d͡ʒaɪgæntoʊ/. Origin: Ancient Greek γίγας, γῐ́γᾰντος (gígas, gigantos). Meaning: giant, of a giant, respectively. Used for large species.Examples: Giganotosaurus ("giant southern lizard"); Gigantopithecus ("giant ape"); Gigantoraptor ("giant seizer")-gnath-, gnatho-, -gnathus: Pronunciation: /neɪθ/, /neɪθoʊ/, /neɪθəs/ (or /gneɪθəs/). Origin: Ancient Greek γνάθος (gnáthos). Meaning: jaw.Examples: Caenagnathasia ("recent Asian jaw"); Gnathostoma ("jaw mouth"); Compsognathus ("elegant jaw")hemi-: Pronunciation: /hɛmi/. Origin: Ancient Greek ἡμι- (hēmi-). Meaning: half.Examples: Hemicyon ("half-dog"); hemichordate ("half-chordate"); Hemiptera ("half-wing")hippus, hippo-: Pronunciation: /ἵππος/. Origin: Ancient Greek ἵππος (híppos). Meaning: horseExamples: Eohippus ("dawn horse"); Hippodraco ("horse dragon"); Hippopotamus ("river horse")hyl-, hylo-: Pronunciation: /haɪl/, /haɪloʊ/ (or /haɪlɒ/). Origin: Ancient Greek ὕλη ("húlē"). Meaning: wood, forest.Examples: Hylonomus ("forest dweller"); Hylobates ("forest walker"); Hylarana ("forest frog")-ia: Pronunciation: /iːə/. Origin: Ancient Greek -ια, -εια (-ia, -eia). Meaning: an abstraction usually used as an honorific for a person or place.Examples: Dickinsonia ("for Dickinson"); Cooksonia ("for Cookson"); Coloradia ("for Colorado"); Edmontonia ("for Edmonton")ichthyo-, -ichthys: Pronunciation: /ɪkθioʊs/, /ɪkθis/. Origin: Ancient Greek ἰχθῦς (ikhthûs). Meaning: fish. The suffix "-ichthys" is used for fish, while the prefix "ichthyo-", while used for fish, is also used for fish-like creatures.Examples: Ichthyosaurus ("fish lizard"); Leedsichthys ("Leeds's fish"); Haikouichthys ("Haikou fish")-lania, Pronunciation: /læniːə/, Origin: Ancient Greek ἀλαίνειν (alaínein): Meaning: to wander. Used for animals that are found in most places around continents.Examples: Meiolania ("weak wanderer"); Megalania ("great wanderer")-lepis, lepido-: Pronunciation: /lɛpɪs/ /lɛpɪdoʊ/ (or /lɛpɪdɒ/). Origin: Ancient Greek λεπίς (lepis). Meaning: scale.Examples: Mongolepis ("Mongol scale"); Polymerolepis ("many part scale"); Lepidosauria ("scaled lizards"); Lepidoptera ("scaled wing"); Lepidodendron ("scaled tree")-lestes: Pronunciation: /lɛstiːz/. Origin: Ancient Greek λῃστής (lēistḗs). Meaning: robber.Examples: Carpolestes ("fruit robber"); Ornitholestes ("bird robber"); Sarcolestes ("flesh robber"); Necrolestes ("grave robber")long: Pronunciation: /lʊng/. Origin: Mandarin long (龙/龍). Meaning: dragon. Used for dinosaur finds in ChinaExamples: Mei long ("sleeping dragon"); Bolong ("small dragon"); Zuolong ("Zuo's dragon")-lopho-, -lophus: Pronunciation: /lɒfoʊ/, /ləfəs/. Origin: Ancient Greek λόφος (lóphos). Meaning: A bird's crest. Used for animals with crests on their heads.Examples: Dilophosaurus ("two-crested lizard"); Brachylophosaurus ("short-crested lizard"); Saurolophus ("lizard crest")macro-: Pronunciation: /mækroʊ/. Origin: Ancient Greek μακρός (makrós). Meaning: (correctly) long; (usually) large.Examples: macropod ("big foot"); Macrodontophion ("big tooth snake"); Macrogryphosaurus ("big enigmatic lizard")-maia, maia-: Pronunciation: /meiə/ Origin: Ancient Greek Μαῖα (Maîa). Meaning: Originally the mother of Hermes in Greek mythology and the goddess of growth in Roman mythology, alternatively spelled Maja. Frequently used to indicate maternal roles, this word should not be construed as translating directly to "mother" (Latin māter; Ancient Greek μήτηρ mḗtēr); aside from being a proper name, in Ancient Greek "maîa" can translate to "midwife" or "foster mother" and was used as an honorific address for older women, typically translated into English as "Good Mother".Examples: Maiasaura ("Good Mother/Maia's lizard"); Eomaia ("dawn Maia"); Juramaia (Jurassic Maia")mega-, megalo-: Pronunciation: /mɛga/, /mɛgaloʊ̯/. Origin: Ancient Greek μέγας, μεγάλη (mégas, megálē). Meaning: big.Examples: Megarachne ("big spider"); Megalosaurus ("big lizard"); Megalodon ("big tooth")micro-: Pronunciation: /maɪkroʊ̯/. Origin: Ancient Greek μικρός (mikrós). Meaning: "small".Examples: Microraptor ("small seizer") Microvenator ("small hunter"); Microceratops ("small horned face")mimo-, -mimus: /maɪmoʊ̯/, /maɪməs/. Origin: Latin mimus. Meaning: actor. Used for creatures that resemble others.Examples: Struthiomimus; ("ostrich mimic"); Ornithomimus ("bird mimic"); Gallimimus ("chicken mimic"); ornithomimosaur ("bird mimic lizard")-monas, -monad: Pronunciation: /moʊnas/, /monas/, /moʊnad/, /monad/. Origin: Ancient Greek μονάς (monás). Meaning: unit. Used for single-celled organisms (mainly protists).Examples: Chlamydomonas ("cloak unit"); Pseudomonas ("false unit"); Metamonad ("encompassing unit")-morph: Pronunciation: /moʊrf/. Origin: Ancient Greek μορφή (morphḗ). Meaning: form, shape. Used for large groups of animals which share a common genetic lineageExamples: crocodylomorphs ("crocodile form"); sauropodomorphs ("sauropod form"); Muscomorpha ("fly form") Dimorphodon ("two forms of teeth")-nax, -anax-: Pronunciation: /ναξ/άναξ/. Origin: Ancient Greek ἄναξ (ánax). Meaning: king.Examples: Lythronax ("gore king") Saurophaganax ("king of the lizard-eaters")-nych, nycho-, -nyx: see -onych, onycho-, -onyx

-odon, -odont, -odonto-: Pronunciation: /oʊdɒn/, /oʊdɒnt/, /oʊdɒntoʊ/. Origin: Ancient Greek ὀδούς (odoús). Meaning: tooth.Examples: Dimetrodon ("two-measures of teeth"), cynodont ("dog tooth") Carcharodontosaurus ("serrated tooth lizard")-oides, -odes: Pronunciation: /oiːdiːz/, /oʊːdiːz/. Origin: Ancient Greek εἶδος (eîdos). Meaning: likeness. Used for species that resemble other species.Examples: Hypocnemoides ("like Hypocnemis"); Aetobarbakinoides ("like the long-legged buzzard"); Callianthemoides ("like Callianthemum"); Argyrodes ("like silver")onycho-, -onychus, -onyx: /ɒnikoʊ/, /ɒnikəs/ (or /ɒnaɪkoʊ/, ɒnaɪkəs/), /ɒniks/. Origin: Ancient Greek ὄνυξ (ónux). Meaning: claw.Examples: Deinonychus ("terrible claw"); Euronychodon ("European claw tooth"); Nothronychus ("sloth claw"), Baryonyx ("heavy claw")-ops: Pronunciation: /ɒps/. Origin: Ancient Greek ὄψ (óps). Meaning: face.Examples: Triceratops ("three-horned face"); Moschops ("calf face"); Spinops ("spine face")-ornis, ornith-, ornitho-: Pronunciation: /oʊ̯rnɪs/, /oʊ̯rnɪθ/, /oʊ̯rnɪθoʊ̯/. Origin: Ancient Greek ὄρνις, ὄρνιθος (órnis, órnithos). Meaning: bird, of a bird respectively. "ornith-" and "ornitho-" are generally used for animals with birdlike characteristics; the suffix "-ornis" is generally applied to fossil bird species.Examples: ornithischian ("bird-hipped"); Ornithocheirus ("bird-hand"); Eoconfuciusornis ("Confucius's dawn bird")pachy-: Pronunciation: /pæki/ Origin: Ancient Greek παχύς (pakhús). Meaning: thick.Examples: Pachycephalosaurus ("thick-headed lizard"); Pachylemur ("thick lemur"); Pachyuromys ("thick tailed mouse")para-: Pronunciation: /pærɑː/ Origin: Ancient Greek παρά (pará). Meaning: near. Used for species that resemble previously named species.Examples: Paranthodon ("near Anthodon"); Pararhabdodon ("near Rhabdodon"); Parasaurolophus ("near Saurolophus)"-pelta: Pronunciation: /pɛltə:/ Origin: Ancient Greek πέλτη (péltē). Meaning: shield. Frequently used for ankylosaurs.Examples: Sauropelta ("lizard shield"); Dracopelta ("dragon shield"); Cedarpelta ("Cedar shield")-pithecus: Pronunciation: /piθəkəs/. Origin: Ancient Greek πίθηκος (píthēkos). Meaning: ape.Examples: Australopithecus ("southern ape"); Ardipithecus ("floor ape"); Gigantopithecus ("giant ape")platy-: Pronunciation: /ˈplætɪ/. Origin: Ancient Greek πλατύς (platús). Meaning: flat. Used for creatures that are flat or have flat parts.Examples: Platyhelminthes ("flat worm"); Platybelodon ("flat spear-tusk"); Platycodon ("flat bell"); Platypus ("flat foot)plesio-, plesi-: Pronunciation: /pliːziːoʊ/, /pliːz/ (or pliːʒ/). Origin: Ancient Greek πλησίον (plēsíon). Meaning: near. Used for species that bear similarities to other species.Examples: Plesiosaurus ("near lizard"); Plesiorycteropus ("near aardvark"); Plesiobaena ("near Baena"); Plesiadapis ("near Adapis")-pod, podo-, -pus: Pronunciation: /pɒd/, /pɒdoʊ/, /pʊs/. Origin: Ancient Greek πούς, ποδός (poús, podós). Meaning: foot, of the foot, respectively.Examples: Ornithopod ("bird foot"); Brachypodosaurus ("short footed lizard"); Moropus ("slow foot")pro-, protero-: pronunciation: /proʊ̯/, /proʊ̯tεroʊ̯/. Origin: Ancient Greek πρό, πρότερος (pró, próteros). Meaning: before. Usually used for ancestral forms.Examples:Proterosuchus ("before crocodile"); Procompsognathus ("before elegant jaw"); Prosaurolophus ("before lizard crest")proto-: Pronunciation: /proʊtoʊ/. Origin: Ancient Greek πρῶτος (prōtos). Meaning: first. Used for early appearances in the fossil record.Examples: Protoceratops ("first horned face"); Protognathosaurus ("first jaw lizard"); Protohadros ("first hadrosaur")psittaco-, -psitta: Pronunciation: /sitɑːkoʊ/, /psitə/. Origin: Ancient Greek ψιττακός (psittakós). Meaning: parrot. "Psittaco-" is used for parrot-like creatures, while the suffix "psitta" is used for parrots.Examples: Psittacosaurus ("parrot lizard"); Cyclopsitta ("Cyclops parrot"); Xenopsitta ("strange parrot").pter-, ptero-, -pterus, pteryg-, -ptera, -pteryx. Pronunciation: /ter/, /teroʊ/, /pterəs/, /terɪg/, /pterɪx/. Origin: Ancient Greek πτέρυξ, πτέρυγος (pterux, ptérugos). Meaning: wing, of a wing, respectively. Used for many winged creatures, but also expanded to mean "fin", and used for many undersea arthropods.Examples: Pteranodon ("toothless wing"); Pterodactylus ("winged finger"); Eurypterus ("wide wing" or fin); Pterygotus ("winged" or finned); Coleoptera ("sheathed wing"); Archaeopteryx ("ancient wing"); Stenopterygius ("narrow finned")-pus: see: -pod, -podo-, -pus.-raptor, raptor-: Pronunciation: /ræptər/. Origin: Latin raptor. Meaning: "seizer, stealer". Frequently used for dromaeosaurids or similar animals. The term "raptor" by itself may also be used for a dromeosaurid, a Velociraptor, or originally, a bird of prey.Examples: Velociraptor ("swift seizer"); Utahraptor ("Utah seizer"); Raptorex ("seizer king")-rex: Pronunciation: /rεks/. Origin: Latin rex. Meaning: king. Often used for large or impressive animals.Examples: Raptorex ("seizer king"); Dracorex ("dragon king"); Tyrannosaurus rex ("tyrant lizard king")-rhina, rhino-, -rhinus: Pronunciation: /raɪnə/ /raɪnoʊ̯/, /raɪnəs/. Origin: Ancient Greek ῥίς (rhís). Meaning: nose.Examples: Altirhinus ("high nose"); Pachyrhinosaurus ("thick-nosed lizard"); Lycorhinus ("wolf nose"); Arrhinoceratops ("noseless horned face"); Cretoxyrhina ("Cretaceous sharp nose"); Rhinoceros ("nose horn")rhodo-: Pronunciation: /roʊdoʊ/, /rodoʊ/. Origin: Ancient Greek ῥόδον (rhódon). Meaning: "rose". Used for red-colored organisms.Examples: Rhododendron ("rose tree"); Rhodophyta ("rose plant"); Rhodomonas ("rose unit")-rhynchus: Pronunciation: /rɪnkəs/. Origin: Ancient Greek ῥύγχος (rhúgkhos). Meaning: "beak", "snout".Examples: Rhamphorhynchus ("prow beak"); Aspidorhynchus ( "shield snout"); Ornithorhynchus ("bird beak")sarco-: Pronunciation: /sɑːrkʊ/. Origin: Ancient Greek σάρξ (sárx). Meaning: flesh. Used for flesh-eating animals or animals and plants with fleshy partsExamples: Sarcophilus ("flesh-loving"); Sarcopterygii ("fleshy fin"); Sarcosuchus ("flesh crocodile")saur, sauro-, -saurus: Pronunciation: /sɔər/, /sɔəroʊ/, /sɔərəs/. Origin: Ancient Greek σαῦρος (saûros). Meaning: lizard. Used for dinosaurs and other extinct reptiles.Examples: Dinosaur ("terrible lizard") Mosasaur ("Meuse lizard"), Tyrannosaurus("tyrant lizard"), Allosaurus("different lizard") Sauroposeidon ("Poseidon lizard")smilo-, -smilus: Pronunciation: /smaɪloʊ/, /smaɪləs/. Origin: Ancient Greek σμίλη (smílē). Meaning: a carving knife or chisel. Used for animals with sabre teeth.Examples: Smilodon ("knife tooth"); Smilosuchus ("knife crocodile"); Thylacosmilus ("pouched knife"); Xenosmilus ("strange knife")-spondylus: Pronunciation: /spɒndələs/. Origin: Ancient Greek σπόνδυλος (spóndulos). Meaning: vertebra.Examples: Streptospondylus ("backwards vertebra"); Massospondylus ("longer vertebra"); Bothriospondylus ("excavated vertebra")squali-, squalo-: Pronunciation: /skweɪlɪ/, /skweɪloʊ/ . Origin: Latin squalus. Meaning: a kind of sea fish. Used for shark like creatures.Examples: Squalodon ("shark tooth") Squaliformes ("shark form"); Squalicorax ("shark raven") Squalomorphii ("shark shape")stego-, -stega: Pronunciation: /stɛgoʊ/, /stɛgə/. Origin: Ancient Greek στέγη (stégē). Meaning: roof. Used for armoured or plated animals.Examples: Stegosaurus ("roofed lizard"); Ichthyostega ("roofed fish"); Acanthostega ("spine roof")strepto-: Pronunciation: /streptoʊ/, /strepto/. Origin: Ancient Greek στρεπτός (streptós). Meaning: twisted, bent.Examples: Streptophyta ("bent plant"); Streptococcus ("twisted granule"); Streptospondylus ("twisted vertebra")-stoma, -stome, -stomus: Pronunciation: /stoʊma/, /stoʊm/, /stoʊməs/. Origin: Ancient Greek στόμα (stóma). Meaning: mouth.Examples: deuterostome (second mouth); Gnathostoma ("jaw mouth") Anastomus ("on mouth")sucho-, -suchus: Pronunciation: /sjuːkoʊ/, /sjuːkəs/. Origin: Ancient Greek σοῦχος (soûkhos). Meaning:: Originally the Ancient Greek name for the Ancient Egyptian crocodile-headed god, Sobek. Used to denote crocodilians or crocodile-like animals.Examples: Deinosuchus ("terrible crocodile") Anatosuchus ("duck crocodile"), Suchomimus ("crocodile mimic")-teuthis: Pronunciation: /tjuːθɪs/. Origin: Ancient Greek τευθίς (teuthís). Meaning: squid. Used for squids and similar cephalopods.Examples: Gonioteuthis ("narrow squid") Architeuthis ("ruling squid") Vampyroteuthis ("vampire squid"); Cylindroteuthis ("cylindrical squid")thero-, -therium. Pronunciation: /θɛroʊ/, /θiːrɪəm/. Origin: Ancient Greek θήρ (thḗr). Meaning: beast. Used for supposedly monstrous animals. The suffix "-therium" is often used to denote extinct mammals.Examples: theropod ("beast foot"), Megatherium ("big beast") Brontotherium ("thunder beast"); Uintatherium ("beast of the Uinta mountains")thylac-: Pronunciation: /θaɪlæk/. Origin: Ancient Greek θύλακος (thúlakos). Meaning: a sack. In the sense of "pouch", used for marsupials.Examples: Thylacine ("pouched one"); Thylacoleo ("pouched lion"); Thylacosmilus ("pouched knife")tri-: Pronunciation: /traɪ/. Origin: Ancient Greek τρία (tría). Meaning: three.Examples: Triceratops ("three-horned face"); Triconodon ("three coned teeth"); trilobite ("three lobes")titano-, -titan: Pronunciation: /taɪtænoʊ/, /taɪtən/. Origin: Ancient Greek Τιτάν, Τιτᾶνος (Titán, Titânos). Meaning: Titan, of the Titan, respectively. Used for large animals.Examples: Titanosaurus ("Titan lizard"); Giraffatitan ("giraffe Titan"); Anatotitan ("duck Titan"); Titanoboa ("Titanic boa")tyranno-, -tyrannus: Pronunciation: /taɪrænoʊ/, /taɪrænəs/. Origin: Ancient Greek τύραννος (túrannos). Meaning: tyrant. Used for animals similar to Tyrannosaurus.Examples: Tyrannosaurus ("tyrant lizard"); Nanotyrannus ("dwarf tyrant"); Tyrannotitan ("Titanic tyrant")veloci-: Origin: Latin velox. Meaning: speed.Example: Velociraptor ("quick thief"); Velocisaurus ("swift lizard")-venator: Pronunciation: /vɛnətər/. Origin: Latin venator. Meaning: hunter.Examples: Afrovenator ("African hunter"); Juravenator ("Jura hunter"); Scorpiovenator ("scorpion hunter"); Neovenator ("new hunter"); Concavenator ("Cuenca hunter")xeno-: Pronunciation: /zinoʊ/. Origin: Ancient Greek ξένος (xénos). Meaning: strange, stranger. Used for organisms that exhibit unusual traits for their class.Examples: Xenosmilus ("strange knife"); Xenotarsosaurus ("strange ankled lizard"); Xenopsitta ("strange parrot"); Xenocyon ("strange dog"); Xenokeryx ("strange horn"); Xenostega ("strange roof"); Xenohyla ("strange hynadae"); Xenozancla ("strange animal"); Xenodermus ("strange mover")-zoon, -zoa: Pronunciation: /zoʊɑːn/, /zoʊə/. Origin: Ancient Greek ζῷον (zōion). Meaning: animal. Used for broad categories of animals, or in certain names of animals.Examples: Metazoa ("encompassing animals"); Parazoa ("near animals"); Ecdysozoa ("moulting animals"); Yunnanozoon ("animal from Yunnan"); Yuyuanozoon ("animal from Yu Yuan")

Magnosaurus

Magnosaurus (meaning 'large lizard') was a genus of basal tetanuran theropod dinosaur from the Middle Jurassic of England. It is based on fragmentary remains and has often been confused with or included in Megalosaurus.

Megalosauridae

Megalosauridae is a monophyletic family of carnivorous theropod dinosaurs within the order Megalosauroidea, closely related to the family Spinosauridae. Some members of this family include Megalosaurus, Torvosaurus, Eustreptospondylus, and Afrovenator. Appearing in the Middle Jurassic, megalosaurids were among the first major radiation of large theropod dinosaurs, although they became extinct by the end of the Jurassic period. They were a relatively primitive group of basal tetanurans containing two main subfamilies, Megalosaurinae and Afrovenatorinae, along with the basal genus Eustreptospondylus, an unresolved taxon which differs from both subfamilies.The defining megalosaurid is Megalosaurus bucklandii, first named and described in 1824 by William Buckland after multiple finds in Stonesfield, Oxfordshire, UK. Megalosaurus was the first formally described dinosaur and was the basis for the establishment of the clade Dinosauria. It is also one of the largest known Middle Jurassic carnivorous dinosaurs, with the best-preserved femur at 805 mm and a proposed body mass of around 943 kg. Megalosauridae is recognized as a mainly European group of dinosaurs, based on fossils found in France and the UK. However, recent discoveries in Niger have led some to consider the range of the family. Megalosaurids appeared right before the split of the supercontinent Pangaea into Gondwana and Laurasia. These large theropods therefore may have dominated both halves of the world during the Jurassic.The family Megalosauridae was first defined by Thomas Huxley in 1869, yet it has been contested throughout history due to its role as a ‘waste-basket’ for many partially described dinosaurs or unidentified remains. In the early years of paleontology, most large theropods were grouped together and up to 48 species were included in the clade Megalosauria, the basal clade of Megalosauridae. Over time, most of these taxa were placed in other clades and the parameters of Megalosauridae were narrowed significantly. However, some controversy remains over whether Megalosauridae should be considered its own distinct group, and dinosaurs in this family remain some of the most problematic taxa in all Dinosauria. Some paleontologists, such as Paul Sereno in 2005, have disregarded the group due to its shaky foundation and lack of clarified phylogeny. However, recent research by Carrano, Benson, and Sampson has systematically analyzed all basal tetanurans and determined that Megalosauridae should exist as its own family.

Megalosauroidea

Megalosauroidea (meaning 'great/big lizard forms') is a superfamily (or clade) of tetanuran theropod dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period. The group is defined as Megalosaurus bucklandii and all taxa sharing a more recent common ancestor with it than with Allosaurus fragilis or Passer domesticus. Members of the group include Spinosaurus, Megalosaurus, and Torvosaurus.

Megalosaurus

Megalosaurus (meaning "Great Lizard", from Greek μέγας, megas, meaning 'big', 'tall' or 'great' and σαῦρος, sauros, meaning 'lizard') is an extinct genus of large meat-eating theropod dinosaurs of the Middle Jurassic period (Bathonian stage, 166 million years ago) of Southern England. Although fossils from other areas have been assigned to the genus, the only certain remains of Megalosaurus come from Oxfordshire and date to the late Middle Jurassic.

The earliest possible fossils of the genus came from the Taynton Limestone Formation. One of these was the lower part of a femur, discovered in the 17th century. It was originally described by Robert Plot as a thighbone of a Roman war elephant, and then as a biblical giant. The first scientific name given for it, in the 18th century, was Scrotum humanum, created by Richard Brookes as a caption; however, this is not considered valid today.

Megalosaurus was, in 1824, the first genus of non-avian dinosaur to be validly named. The type species is Megalosaurus bucklandii, named in 1827. In 1842, Megalosaurus was one of three genera on which Richard Owen based his Dinosauria. On Owen's directions a model was made as one of the Crystal Palace Dinosaurs, which greatly increased the public interest for prehistoric reptiles. Subsequently, over fifty other species would be classified under the genus, originally because dinosaurs were not well known, but even during the 20th century after many dinosaurs had been discovered. Today it is understood these additional species were not directly related to M. bucklandii, which is the only true Megalosaurus species. Because a complete skeleton of it has never been found, much is still unclear about its build.

The first naturalists who investigated Megalosaurus mistook it for a gigantic lizard of twenty metres length. In 1842, Owen concluded that it was no longer than nine metres, standing on upright legs. He still thought it was a quadruped, though. Modern scientists, by comparing Megalosaurus with its direct relatives in the Megalosauridae, were able to obtain a more accurate picture. Megalosaurus was about six metres long, weighing about seven hundred kilogrammes. It was bipedal, walking on stout hindlimbs, its horizontal torso balanced by a horizontal tail. Its forelimbs were short, though very robust. Megalosaurus had a rather large head, equipped with long curved teeth. It was generally a robust and heavily muscled animal.

Pelorosaurus

Pelorosaurus ( pə-LORR-oh-SOR-əs; meaning "monstrous lizard") is a genus of titanosauriform sauropod dinosaur. Remains referred to Pelorosaurus date from the Early Cretaceous period, about 140-125 million years ago, and have been found in England and Portugal.

The name Pelorosaurus was one of the first to be given to any sauropod. Many species have been assigned to the genus historically, but most are currently considered to belong to other genera. Problematically, the first named species of Pelorosaurus, P. conybeari, is a junior synonym of Cetiosaurus brevis.

Piveteausaurus

Piveteausaurus (meaning "Jean Piveteau's lizard") is a genus of theropod dinosaur known from a partial skull discovered in the Middle Jurassic Marnes de Dives formation of Calvados, in northern France.

Poekilopleuron

Poekilopleuron (meaning "varied ribs") is an extinct genus of megalosauroid tetanuran theropod dinosaur, which lived during the middle Bathonian of the Jurassic, about 168 to 166 million years ago. The genus has been used under many different spelling variants, although only one, Poekilopleuron, is valid. The type species is P. bucklandii, named after William Buckland, and many junior synonyms of it have also been erected. Few material is currently known, as the holotype was destroyed in World War II, although many casts of the material still exist.

Thecodontosaurus

Thecodontosaurus ("socket-tooth lizard") is a genus of herbivorous basal sauropodomorph dinosaur that lived during the late Triassic period (Rhaetian age).

Its remains are known mostly from Triassic "fissure fillings" in South England. Thecodontosaurus was a small bipedal animal, about 2 m (6.5 ft) long. It is one of the first dinosaurs to be discovered and is one of the oldest that existed. Many species have been named in the genus, but only the type species Thecodontosaurus antiquus is seen as valid today.

Piatnitzkysauridae
Megalosauria

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